// Assuming this is in the same area as type hinting, in catch blocks:

try {

// ..

} catch (PDOException$e) {

// ..

}

try {

// ..

} catch (asdf\PDOException$e) {

// ..

}

try {

// ..

} catch (\asdf\foo\PDOException$e) {

// ..

}

try {

// ..

} catch (namespace\PDOException$e) {

// ..

}

// Also while technically not an issue, the namespace keyword isn't actually interpreted as a library keyword and rather as if it was a user defined namespace. (http://www.php.net/manual/en/language.namespaces.nsconstants.php)

$keyword=new\MyClass();

$keyword=newnamesace\MyClass();

$blah=newnamespace\MyClass();

$blah=new\namespace\MyClass();

$blah=newfoo\namespace\MyClass();

$blah=newblah();

$blah=newblah\blah();

$blah=newblah\$blah\$blah\blah();

if ($test==1) {

} elseif (123===$foo) {

} elseif (CONST) {

} else {

}

if ($blahinstanceofMyClass) {

}

if ($blahinstanceoffoo\MyClass) {

}

if ($blahinstanceofnamespace\foo\MyClass) {

}

if ($blahinstanceof$b) {

}

foo(&$blah); // Ampersand should be invalid.deprecated.call-time-pass-by-reference.php